Portion of a display screen with a graphical user interface



FIG. 1 is a front view of a portion of a display screen with a graphical user interface showing a first embodiment of our new design.

FIG. 2 is a front view of a portion of a display screen with a graphical user interface showing a second embodiment of our new design; and,

FIG. 3 is a front view of a portion of a display screen with a graphical user interface showing a third embodiment of our new design.

The broken-line showing of the portion of the display screen and the small “X”s are for the purpose of illustrating environmental structure and forms no part of the claimed design. 

CLAIM The ornamental design for a portion of a display screen with a graphical user interface, as shown and described. 